Hi,
I had my 996 TT Tip at Porsche for the 30.000 miles service, Got it back two weeks ago and now it stumbles when I kick down. the gearbox shifts back and the engine is seriously stumbling.... Any Ideas? (there is no light coming on).

Thanks

 

May be the spark plugs. Should have been changed during 30,000mile service. Good luck.

 

Since I payed 2K for the service I think they should have changed the plugs, but how can I tell???

 

Sounds like plugs. I'd call the dealer and ask if the plugs were changed. They should do them at the 30k check up. Then I would pull one of the outer plugs just to double check.

 

This is highly unlikely but my buddy would always run a very small amount of
fuel in his car (versus filling it up), and it was stumbling due to fuel starvation.
Otherwise you should have gotten plugs with the 30K?
Have a scan tool put on it.

 

They have done the plugs!! Fuel isn't the problem... Any other ideas?? Could it be the MAF ?

 

Yes, MAF,

At my dealership it costs $520 plus tax with a 15% discount (I bought one yesterday
for a friend)

MK

 

Check for boost leaks.

 

The MAF is ok! How do I check for boost leaks???? Any other ideas?? ( when accelerating from 0 everything looks fine the stumbling shows when the tip has changed to lower gears...)